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authorAndrea Parri <parri.andrea@gmail.com>2020-01-09 19:06:49 +0300
committerDaniel Lezcano <daniel.lezcano@linaro.org>2020-01-16 21:09:02 +0300
commit0af3e137c144377fbaf5025ba784ff5ba7ad40c9 (patch)
treee7061dcf97329e37ca4a45d5882a6582765da744 /drivers/clocksource
parentb9c60a741f06eda56d12c7216accb317b74266b4 (diff)
downloadlinux-0af3e137c144377fbaf5025ba784ff5ba7ad40c9.tar.xz
clocksource/drivers/hyper-v: Untangle stimers and timesync from clocksources
hyperv_timer.c exports hyperv_cs, which is used by stimers and the timesync mechanism. However, the clocksource dependency is not needed: these mechanisms only depend on the partition reference counter (which can be read via a MSR or via the TSC Reference Page). Introduce the (function) pointer hv_read_reference_counter, as an embodiment of the partition reference counter read, and export it in place of the hyperv_cs pointer. The latter can be removed. This should clarify that there's no relationship between Hyper-V stimers & timesync and the Linux clocksource abstractions. No functional or semantic change. Suggested-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Andrea Parri <parri.andrea@gmail.com> Reviewed-by: Michael Kelley <mikelley@microsoft.com> Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Link: https://lore.kernel.org/r/20200109160650.16150-2-parri.andrea@gmail.com
Diffstat (limited to 'drivers/clocksource')
-rw-r--r--drivers/clocksource/hyperv_timer.c36
1 files changed, 23 insertions, 13 deletions
diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 12d75b50a317..42748adccc98 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c
@@ -66,7 +66,7 @@ static int hv_ce_set_next_event(unsigned long delta,
{
u64 current_tick;
- current_tick = hyperv_cs->read(NULL);
+ current_tick = hv_read_reference_counter();
current_tick += delta;
hv_init_timer(0, current_tick);
return 0;
@@ -304,8 +304,8 @@ EXPORT_SYMBOL_GPL(hv_stimer_global_cleanup);
* Hyper-V and 32-bit x86. The TSC reference page version is preferred.
*/
-struct clocksource *hyperv_cs;
-EXPORT_SYMBOL_GPL(hyperv_cs);
+u64 (*hv_read_reference_counter)(void);
+EXPORT_SYMBOL_GPL(hv_read_reference_counter);
static union {
struct ms_hyperv_tsc_page page;
@@ -318,7 +318,7 @@ struct ms_hyperv_tsc_page *hv_get_tsc_page(void)
}
EXPORT_SYMBOL_GPL(hv_get_tsc_page);
-static u64 notrace read_hv_clock_tsc(struct clocksource *arg)
+static u64 notrace read_hv_clock_tsc(void)
{
u64 current_tick = hv_read_tsc_page(hv_get_tsc_page());
@@ -328,9 +328,14 @@ static u64 notrace read_hv_clock_tsc(struct clocksource *arg)
return current_tick;
}
+static u64 notrace read_hv_clock_tsc_cs(struct clocksource *arg)
+{
+ return read_hv_clock_tsc();
+}
+
static u64 read_hv_sched_clock_tsc(void)
{
- return read_hv_clock_tsc(NULL) - hv_sched_clock_offset;
+ return read_hv_clock_tsc() - hv_sched_clock_offset;
}
static void suspend_hv_clock_tsc(struct clocksource *arg)
@@ -359,14 +364,14 @@ static void resume_hv_clock_tsc(struct clocksource *arg)
static struct clocksource hyperv_cs_tsc = {
.name = "hyperv_clocksource_tsc_page",
.rating = 400,
- .read = read_hv_clock_tsc,
+ .read = read_hv_clock_tsc_cs,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
.suspend= suspend_hv_clock_tsc,
.resume = resume_hv_clock_tsc,
};
-static u64 notrace read_hv_clock_msr(struct clocksource *arg)
+static u64 notrace read_hv_clock_msr(void)
{
u64 current_tick;
/*
@@ -378,15 +383,20 @@ static u64 notrace read_hv_clock_msr(struct clocksource *arg)
return current_tick;
}
+static u64 notrace read_hv_clock_msr_cs(struct clocksource *arg)
+{
+ return read_hv_clock_msr();
+}
+
static u64 read_hv_sched_clock_msr(void)
{
- return read_hv_clock_msr(NULL) - hv_sched_clock_offset;
+ return read_hv_clock_msr() - hv_sched_clock_offset;
}
static struct clocksource hyperv_cs_msr = {
.name = "hyperv_clocksource_msr",
.rating = 400,
- .read = read_hv_clock_msr,
+ .read = read_hv_clock_msr_cs,
.mask = CLOCKSOURCE_MASK(64),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
@@ -399,7 +409,7 @@ static bool __init hv_init_tsc_clocksource(void)
if (!(ms_hyperv.features & HV_MSR_REFERENCE_TSC_AVAILABLE))
return false;
- hyperv_cs = &hyperv_cs_tsc;
+ hv_read_reference_counter = read_hv_clock_tsc;
phys_addr = virt_to_phys(hv_get_tsc_page());
/*
@@ -417,7 +427,7 @@ static bool __init hv_init_tsc_clocksource(void)
hv_set_clocksource_vdso(hyperv_cs_tsc);
clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
- hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_sched_clock_offset = hv_read_reference_counter();
hv_setup_sched_clock(read_hv_sched_clock_tsc);
return true;
@@ -439,10 +449,10 @@ void __init hv_init_clocksource(void)
if (!(ms_hyperv.features & HV_MSR_TIME_REF_COUNT_AVAILABLE))
return;
- hyperv_cs = &hyperv_cs_msr;
+ hv_read_reference_counter = read_hv_clock_msr;
clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
- hv_sched_clock_offset = hyperv_cs->read(hyperv_cs);
+ hv_sched_clock_offset = hv_read_reference_counter();
hv_setup_sched_clock(read_hv_sched_clock_msr);
}
EXPORT_SYMBOL_GPL(hv_init_clocksource);